This invention relates generally to wind turbines, and more particularly, to a system and method for acquiring trip event data in wind turbines.
Recently, wind turbines have received increased attention as an environmentally safe and relatively inexpensive alternative energy source with zero green house gas (GHG) emissions. With this growing interest, considerable efforts have been made to develop wind turbines that are reliable and efficient.
Generally, wind turbines use the wind to generate electricity. The wind turns one or more blades connected to a hub, where the blades and hub can comprise a rotor. The spin of the blades caused by the wind spins a shaft connected to the rotor, which connects to a generator that generates electricity. Specifically, the rotor is mounted within a housing or nacelle, which is positioned on top of a truss or tubular tower. Utility grade wind turbines (e.g., wind turbines designed to provide electrical power to a utility grid) can have large rotors (e.g., 30 or more meters in diameter). Blades on these rotors transform wind energy into a rotational torque or force that drives one or more generators, rotationally coupled to the rotor through a gearbox. The gearbox may be used to step up the inherently low rotational speed of the turbine rotor for the generator to efficiently convert mechanical energy to electrical energy, which is provided to a utility grid. Some turbines utilize generators that are directly coupled to the rotor without using a gearbox.
Power converters are used to transfer the power from the generator to a grid connection. In operation, a required level of energy will pass through a DC link of the power converter. Under certain conditions (e.g., transient power conditions), high power mismatch between the rotor and the grid connection temporally exist and voltage transients become amplified such that a DC link voltage level can increase above normal allowed or rated levels. Thus, wind turbines have to be able to absorb or deflect the excessive power level.
Pitch control subsystems are used to rotate the blades about their axial or longitudinal axis. In some known wind turbines an electronic controller is used in conjunction with a blade pitch mechanism to pitch the blades around their respective longitudinal axes to control the power output of the wind turbine. Motors can be provided to pitch the blades while the rotor is turning. The pitch control subsystem can also be used to feather the blades during storm conditions.
Wind turbine controllers can be used to monitor many operating parameters of the wind turbine, and various environmental conditions (e.g., wind speed, ambient temperature, etc.). In addition, the wind turbine controller can instruct the various wind turbine subsystems to adjust various operating modes to compensate for or react to changing environmental conditions.
It can be seen that some wind turbines comprise three subsystems, the pitch control subsystem, the power converter subsystem and the wind turbine controller subsystem. Sensor data from each of these subsystems can be helpful in determining when and why a fault or trip event occurred. To date, no single system has provided a means for obtaining and consolidating relevant data from each of the three subsystems listed above.
Accordingly, a need exists for an improved system and method for acquiring and analyzing data from multiple sub-systems in a wind turbine.